# Understanding Connection Agreements

A connection agreement acts as a control mechanism for directory replication between the Microsoft Exchange Server version 5.5 directory and the Microsoft Windows 2000 Server Active Directory. The connection agreement defines the following:

- Directory, or directories, to be replicated
- Exchange replication objects
- Windows replication objects
- Replication direction
- Schedule
- Deletion method
- Advanced options

Although only one instance of the ADC can be installed on a single computer running Windows 2000 Server, multiple Connection Agreements can be established. Each Connection Agreement can be configured to perform unique replication tasks. For example, one Connection Agreement can continuously update the Windows 2000 Server Active Directory, while another Connection Agreement can update the Windows contacts to the Exchange directory daily at 6:00 P.M.
You can also establish Primary Connection Agreement. A Primary Connection Agreement creates new objects, while all other Connection Agreements only replicate information to existing objects.

### Related Topics

Set Up a Connection Agreement